Method and apparatus for starting an internal combustion engine

Abstract

A method and apparatus for starting an internal combustion engine is disclosed. A motor is mechanically coupled to the engine, the engine having at least one moveable element mounted in a chamber, the moveable element being operable to cause a changing compression condition within the chamber and being mechanically coupled to a shaft for generating mechanical power. The method involves causing the motor to supply a positioning torque to the engine to move the at least one moveable element into a starting position. The method also involves causing the motor to supply a starting torque to the engine when the at least one moveable element is in the starting position to cause the moveable element to accelerate from the starting position under low compression conditions to generate sufficient momentum to overcome a peak compression condition in the chamber, thereby reducing the starting torque required to start the engine.

What is claimed is: 
     
       1. A method for starting an internal combustion engine, comprising:
 determining, while the engine is stopped, a reference positioning torque to be supplied to the engine by a motor; 
 generating a first motor control signal operable to cause the motor to supply the determined reference positioning torque to the engine in order to move at least one piston of the engine in a direction opposite a compression stroke of the at least one piston; and 
 generating a second motor control signal operable to cause the motor to supply a starting torque to the engine. 
 
     
     
       2. The method of  claim 1 , wherein the starting torque and the reference positioning torque are supplied in opposite directions. 
     
     
       3. The method of  claim 1 , wherein the magnitude of the reference positioning torque is such that the at least one piston of the engine moves to a position at which a force exerted on the at least one piston due to the supplied reference positioning torque matches a counteracting force exerted on the at least one piston as a result of compression in a cylinder of at least one other piston of the engine. 
     
     
       4. The method of  claim 1 , wherein the reference positioning torque is determined based at least in part on a measured temperature of the engine. 
     
     
       5. The method of  claim 1 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a permanent mechanical coupling between the motor and the engine. 
     
     
       6. The method of  claim 1 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a temporary mechanical coupling between the motor and the engine. 
     
     
       7. The method of  claim 1 , further comprising receiving an engine control signal indicating the engine is stopped. 
     
     
       8. The method of  claim 1 , further comprising, after the starting torque is supplied to the engine and the engine is running, configuring the motor to operate in a generator mode such that the motor can convert mechanical energy supplied by the engine into electrical energy. 
     
     
       9. An apparatus for starting an internal combustion engine, comprising:
 a motor operable to supply a reference positioning torque and a starting torque to the engine; 
 a controller configured to communicate with the motor, the controller operable to:
 determine, while the engine is stopped, the reference positioning torque to be supplied to the engine; 
 generate a first motor control signal to be communicated to the motor, the first motor control signal operable to cause the motor to supply the determined reference positioning torque to the engine in order to move at least one piston of the engine in a direction opposite a compression stroke of the at least one piston; and 
 generate a second motor control signal to be communicated to the motor, the second motor control signal operable to cause the motor to supply the starting torque to the engine. 
 
 
     
     
       10. The apparatus of  claim 9 , wherein the starting torque and the reference positioning torque are supplied in opposite directions. 
     
     
       11. The apparatus of  claim 9 , wherein the magnitude of the reference positioning torque is such that the at least one piston of the engine moves to a position at which a force exerted on the at least one piston due to the supplied reference positioning torque matches a counteracting force exerted on the at least one piston as a result of compression in a cylinder of at least one other piston of the engine. 
     
     
       12. The apparatus of  claim 9 , further comprising a temperature sensor operable to measure a temperature of the engine, the reference positioning torque being determined based at least in part on the measured temperature of the engine. 
     
     
       13. The apparatus of  claim 9 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a permanent mechanical coupling between the motor and the engine. 
     
     
       14. The apparatus of  claim 9 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a temporary mechanical coupling between the motor and the engine. 
     
     
       15. The apparatus of  claim 9 , wherein the controller is further operable to receive an engine control signal indicating the engine is stopped. 
     
     
       16. The apparatus of  claim 9 , wherein the controller is further operable to, after the starting torque is supplied to the engine and the engine is running, configure the motor to operate in a generator mode such that the motor can convert mechanical energy supplied by the engine into electrical energy. 
     
     
       17. A vehicle, comprising:
 an internal combustion comprising one or more cylinders; 
 a motor operable to supply a reference positioning torque and a starting torque to the engine; 
 a controller configured to communicate with the motor, the controller operable to:
 determine, while the engine is stopped, the reference positioning torque to be supplied to the engine; 
 generate a first motor control signal to be communicated to the motor, the first motor control signal operable to cause the motor to supply the determined reference positioning torque to the engine in order to move at least one piston of the engine in a direction opposite a compression stroke of the at least one piston; and 
 generate a second motor control signal to be communicated to the motor, the second motor control signal operable to cause the motor to supply the starting torque to the engine. 
 
 
     
     
       18. The vehicle of  claim 17 , wherein the starting torque and the reference positioning torque are supplied in opposite directions. 
     
     
       19. The vehicle of  claim 17 , wherein the magnitude of the reference positioning torque is such that the at least one piston of the engine moves to a position at which a force exerted on the at least one piston due to the supplied reference positioning torque matches a counteracting force exerted on the at least one piston as a result of compression in a cylinder of at least one other piston of the engine. 
     
     
       20. The vehicle of  claim 17 , further comprising a temperature sensor operable to measure a temperature of the engine, the reference positioning torque being determined based at least in part on the measured temperature of the engine. 
     
     
       21. The vehicle of  claim 17 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a permanent mechanical coupling between the motor and the engine. 
     
     
       22. The vehicle of  claim 17 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a temporary mechanical coupling between the motor and the engine. 
     
     
       23. The vehicle of  claim 17 , wherein the controller is further operable to receive an engine control signal indicating the engine is stopped. 
     
     
       24. The vehicle of  claim 17 , wherein the controller is further operable to, after the starting torque is supplied to the engine and the engine is running, configure the motor to operate in a generator mode such that the motor can convert mechanical energy supplied by the engine into electrical energy. 
     
     
       25. The vehicle of  claim 24 , further comprising:
 an energy storage element; and 
 an energy bus operable to supply the electrical energy generated by the motor to the energy storage element. 
 
     
     
       26. An apparatus for starting an internal combustion engine, comprising:
 means for determining, while the engine is stopped, the reference positioning torque to be supplied to the engine; 
 means for generating a first motor control signal to be communicated to the motor, the first motor control signal operable to cause the motor to supply the determined reference positioning torque to the engine in order to move at least one piston of the engine in a direction opposite a compression stroke of the at least one piston; and 
 means for generating a second motor control signal to be communicated to the motor, the second motor control signal operable to cause the motor to supply a starting torque to the engine. 
 
     
     
       27. The apparatus of  claim 26 , wherein the starting torque and the reference positioning torque are supplied in opposite directions. 
     
     
       28. The apparatus of  claim 26 , wherein the magnitude of the reference positioning torque is such that the at least one piston of the engine moves to a position at which a force exerted on the at least one piston due to the supplied reference positioning torque matches a counteracting force exerted on the at least one piston as a result of compression in a cylinder of at least one other piston of the engine. 
     
     
       29. The apparatus of  claim 26 , further comprising means for measuring a temperature of the engine, the reference positioning torque being determined based at least in part on the measured temperature of the engine. 
     
     
       30. The apparatus of  claim 26 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a permanent mechanical coupling between the motor and the engine. 
     
     
       31. The apparatus of  claim 26 , wherein the reference positioning torque and the starting torque are each supplied by the motor to the engine via a temporary mechanical coupling between the motor and the engine. 
     
     
       32. The apparatus of  claim 26 , further comprising means for configuring, after the starting torque is supplied to the engine and the engine is running, the motor to operate in a generator mode such that the motor can convert mechanical energy supplied by the engine into electrical energy.